Means for use in machining two oppositely tapering surfaces of a work piece and in screw threading such surfaces



Gent. 21 1924.

v 512,520 L. N. BURT ET AL I MEANS FOR USE IN MACHINING TWO OPPOSITELY TAPEBING SURFACES OF A WORK PIECE AND IN SCREW THREADING SUCH SURFACES Filed Dec. 4, 1922 5 Sheets-Sheet 1 40/ v46 HHWMHW HHHHHWHP?vL .nTiiflilwltil A W;

MEANS FOR USE IN MACHINING TWO OPPOSITELY TAPERING SURFACES OF A WORK PIECE AND IN SCREW THREADZNG SUCH SURFACES F/G.Z.

Filed 1,5125% BU WT ET A L 5 Shasta-Sheet 2 //v VEN T0 Oct. 21 1924. 1,512,520

L. N. BURT ET AL MEANS FOR USE IN MACHINING TWO OPPOSITELY TAPERING SURFACES OF A WORK PIECE AND IN SCREW THREADING SUCH SURFACES Filed Dec. 4, 1922 3 Sheets-Sheet 5 Patented Oct. 21, 1924.

UNITE!) STATES PATENT QFFICE.

LESLIE NEWMAN BURT AND JAMES EDVJABD EREEBGIRN, OF WESTMINSTER, ENG- LAND, ASSIGNORS TO THE RICHARDS THREAD IVIILLING MACHINE COMPANY (1918) LIMITED, OF WESTMINSTER, ENGLAND.

MEANS FOR USE IN MACHINING TW'O OPPOSITELY 'TAIERING SURFACES OF A WO'ZRK PIECE AND IN SCREW 'THREADING SUCH SURFACES.

Applicatibn filed December 4, 1922.

To ail whom it may concern:

Be it known that we, LESLIE. NEWMAN BURT and Janus EDWARD Fnnunonn, subjects of the King of Great Britain and Ireland, both residing at 222 Outer Temple, Strand, in the city of Westminster, England, have invented new and useful 1niproved Means for use in Machining Two Oppositely Tapering Surfaces of a V-Vork Piece and in Screw Threading Such Surfaces, of which the following is aspecification.

This invention relates to improved means for use in boring or turning two oppositely tapering internal or external surfaces of a work-piece and in screw-threading such surfaces; such operations being effected at a single setting of the work-piece with the aid of a single boring or turning tool or a thread-milling hob or a combinationtool of the character hereinafter described. The invention embraces, moreover, means for auto matically or manually regulating the depth of the screw-threads cut, for permitting angular adjustment of the boring tool about the thread-milling hob Without dismounting the latter or reversing the direction of rotation of the work-piece, and for enabling the normal rotative speed of the latter in either direction to be slightly increased or diminished with a view to eliminating the facets which would otherwise be formed upon the screw-threads. V

In the accompanying drawings, Fig. 1 is a side elevation, partly in vertical section, illustrating a boring and screw-thread milling machine constructed according to our invention, Fig. 2 a corresponding plan, partly in horizontal section, and Fig. a detail view, in vertical section, showing certain gearing employed. Figs. a and 5 are respectively an end elevation and a longitudinal section illustrating in its inoperatve condition manual and automatic mechanism for regulating the depth of the screwthreaded cut, 'whi lst Figs. 6 and 7 are like views, illustrating the operative condition "of the said mechanism.

Referring to Figs. 1, 2 and 3, the drive is transmitted from'a shaft a, by way of the cr0ss-shaft a and the vertical shaft a through gears c and 0 to the shaft 6 which carries a Worm b; the latter driving Serial No. 604,850.

a worm-wheel (Z mounted on the hollow spindle of the headstock. The worm b is feathered upon and rotates with the shaft 6 but is free to slide longitudinally thereon under the influence of the cams b 5 carried by the spur-Wheels 0, 0 which are freely mounted upon the shaft 6 Each of the spur-wheels c, 0 has one tooth moreor one tooth less than the spur-wheel 0 the latter being fast on the shaft 6 Under these conditions, the worm b is driven from the shaft (4 at a speed which is slightly differentiated from that of the cam-faced wheels 0, '0 The rise and fall of the worm b consequently afi ec-ts the rotative speed of the worm-wheel d (see Fig. 2), and the rotative speed of the work-piece is alternatively accelerated and retarded in relation to that of the hob} thereby preventing the formation of facets in the surfaces of the screw-threads out.

Rotative motion is also transmitted from the shaft a, by way of suitable gearing, to a crossshaft c and thence, by way of the wornrwheel e mounted in the carriage f, to the hob-spindle 6 The carriage f is: capable of lateral adjustment along V- guides, carried by a saddle f, and along the cross-shaft e, which is furnished with a spline; whilst longitudinal traverse of the carriage and saddle is effected by means of a worm-wheel g, driven from the shaft a (see Fig. and mounted upon a cross-shaftg carrying a spur-pinion g meshing with a rack 9 The worm-wheel 9 may be disengaged from the cross-shaft g by a friction cone and nutas commonly used on a latheoperated from the frontof the saddle. The lever g is primarily intended for usein reversing the direction of feed of the l1ob-carria-ge5 but when placed in aneutral position, the hob-carriage feed is out of ear.

The headstock carrying the work-piece may be adjusted as regards its angular position, and the machining of the oppositely tapering surfaces is effected by moving the tool diametrically across the interior of the work-piece, the second position of the hob being indicated in broken lines :in Fig. 2.

The boring tool it may be brought into the required positions by rotating its stationary carrier h, which is co-axial with the hobspindle 6 through an angle :of 180, the hob remaining undisturbed, and thus the boring tool can at will be clamped in position to op erate upon the surface to be machined.

The depth to which the thread is to be cut into the work-piece may be set by hand; and for this purpose, we utilize a spindle 7c (see Figs. 5 and 7) arranged within a hollow-threaded sleeve Z0 keyed to the spindle is by means by a spline k adapted to permit their relative axial movement to a limited extent. The hollow threaded sleeve 21 engages with a nut attached to the under side of the hob-spindle arriage e At one e1;- tremity of the spindle 7c, is mounted one member of a clutch, whereof the other member is carried by the spur-wheel l driven from the shaft 9 the clutch members being normally held. out of engagement by means of the spring 972. At the other extremity of the spindle is is transverse key 01, adapted to engage in a slot a formed in the face of plate a attached to the handwheel 0; means, such as the clamping lever 0 being provided whereby the handwheel may, when recpiired, be locked against rotation. For manual control, the screw-threaded sleeve is is operated from the hand-wheel. 0 by way of the transverse key a and the spline For automatic operation in producing the full depth of cut, the knob 70 and hence the spindle a, is moved to the posit-ion shown in Fig. 7, with the effect that the tinnsvcrse key it leaves its slot m and that the handwheel becomes freed. The hand'wheel 0 is then rotated throu h a suitable angle, the

graduation shown in Fi s. 4 and 5 assisting in this settin rotated by Upon the sleeve if being the drive through corresponding angle, the transverse zey n re-enters its slot n thus rendering the clutch inoperat've, cutting out the drive andhring the handwheel l aclr into engagement.

To compensate for error due to wear, the alate n is adjuetaoly mounted with a view to the accurate relation to a As illustrated 7 is also provided for the purpose of feeding the tool in the opposite direction tothat above referred to, or for disconnecting the feed-inotion of the hob-spindle Carr no.

It will be obvious that, by substituting for the hob a boring tool or a suitable milling cutter, the taper surfaces of the workpiece may be bored; and that, without altering the setting of the work-piece in its in .51 lg. a suitable gear chuck, the latter may be adjusted co-axial with that of the tool-carrier 1 and the ends of the work-piece faced.

In cutting a single-start thread with a single-start threaded hob, the work-piece and the hob revolve at the same rotative speed; but Where a multiple-start threaded hole is employed for cutting a single thread in the work-piece, the rotativc speed of llio latter has to be increased in proportion to the number of threads employed in the multiple threaded hob.

1. The herein described means for screw threading two oppositely tapering surfaces of a work-piece at a single setting thereof, such means comprising a bob mounted on a revolving spindle, a cbuclr. adapted to mount the work-piece at an angle oblique o the axis of the hob, means for feeding the bob laterally according to the depth of the out required, and means for adjustino lbo b b lengthwise from :1 position opposite one of the tapering surfaces to a position opposite the other tapering surface, but neither l'lh hob nor the work-piece partaking; of any axial movement during the cutting opera tion.

sui ces of a work-piece at a single set-- ting thereof and with the aid of a single oring tool, the combination. with a revolvg tool-carrier of means for moving the atter axiall for the purpose of engaging! he tool with one or the oloor of too taper 'nr; surfaces. means for moving the toolcarrier laterally for the same purpovo uml .i or use in boring two oppositely taperior rogulatiim; the rilepth of cut. and u rean); clinchwarmer capable of angular l'Ct-Zllfff cutter, he combination, with such cutter. of a carriage wherein the cutterspindle is mounted, xi carriage 'l'ormiul with V-gnides or the like adapted to permit lat eral travel of the carriage. and menus for controlling such. mo ement to r date th denth of cut.

For use in scrow-threading. boring; or turning, two oppositely tapering surfaces of a worl: iece, a spindle arranged within and keyed to a screw-threaded sleeve, and carn ing, as to one GTilllGl'llllfv. a clutch-cont rolled spur-wheel. and, as to its other extremity. u trimsverse hey, a handwhocl with a graduated plate formed wih a slot wherein the transverse lrey normally lies, and means for clamping the bush of the handwheel when required.

LESLH) Nlllllilrill BURT.

Eb EDlVAR-D FRFEBORN. 

